CN220488423U

CN220488423U - Electromagnetic valve

Info

Publication number: CN220488423U
Application number: CN202322155411.5U
Authority: CN
Inventors: 金钜; 王傅钢
Original assignee: Dunan Automotive Thermal Management Technology Co Ltd
Current assignee: Dunan Automotive Thermal Management Technology Co Ltd
Priority date: 2023-06-19
Filing date: 2023-08-10
Publication date: 2024-02-13
Anticipated expiration: 2033-08-10
Also published as: CN220488424U; CN220470772U; CN220470773U; CN220488425U; CN220488422U; CN220470771U

Abstract

The present utility model provides a solenoid valve comprising: the shell component is internally provided with a mounting cavity; the shell component is provided with a first flow port, a second flow port and a main valve port; the on-off assembly is movably arranged in the mounting cavity; the on-off assembly is used for controlling the opening and closing of the main valve port; the on-off assembly comprises a piston body and a pilot valve block fixedly arranged on the piston body, and is provided with a through middle channel; one end of the middle channel is communicated with the first flow port, and the other end of the middle channel is provided with a pilot valve port; the pilot valve port is arranged on the pilot valve block, and at least one part of the middle channel is arranged in the piston body; the one-way valve is movably arranged in the middle channel, so that the middle channel can flow in one way. The on-off assembly is easy to process and shape; the split structure design of the piston body and the pilot valve block enables the processing and forming of the pilot valve port and the middle channel to be more convenient, effectively improves the processing precision of the pilot valve port and the middle channel, and further meets the actual use requirements.

Description

Electromagnetic valve

Technical Field

The utility model relates to the technical field of electromagnetic valves, in particular to an electromagnetic valve.

Background

Currently, solenoid valve products are widely used. Fig. 1 is a schematic cross-sectional view of a conventional solenoid valve in the prior art. As shown in fig. 1, the solenoid valve includes a valve body member 01, a control member 02, and a piston member 03. The valve body part 01 comprises a main valve opening 011, the piston part 03 (corresponding to an on-off assembly in the application) can axially move relative to the valve body part 01, the piston part 03 can be abutted against the main valve opening 011, the piston part 03 comprises a piston 031, a plunger 032 which is positioned in an inner cavity of the piston 031 and can axially move relative to the piston 031, and a gasket 033 which limits the plunger 032 to separate from the piston 031, the piston 031 comprises an upper pilot valve opening 0311 and a lower pilot valve opening 0312, the control part 02 comprises a steel ball 021, the steel ball 021 can be abutted against the upper pilot valve opening 0311, the plunger 032 comprises a conical portion 0321, and the conical portion 0321 can be abutted against the lower pilot valve opening 0312. The machining accuracy of the upper and lower pilot valve portions 0311 and 0312 of the solenoid valve with this structure affects the operation performance of the solenoid valve, but it is inconvenient to machine the lower pilot valve portion 0312 with this structure.

In order to satisfy the bidirectional flow, a conventional solenoid valve is generally provided with a check valve in a piston member (corresponding to an on-off assembly in the present application). On the basis of accommodating the one-way valve, the existing piston part is inconvenient to process, and the upper pilot valve part (for example, a pilot valve port in the application) and the lower pilot valve part (for example, an intermediate channel in the application) are low in processing precision and cannot meet the actual use demands.

Disclosure of Invention

The utility model provides a solenoid valve, which aims to solve the problems that the machining precision of an upper pilot valve opening part and a lower pilot valve opening part of the solenoid valve in the prior art is low and the actual use requirement cannot be met.

In order to solve the above problems, the present utility model provides a solenoid valve comprising: the shell component is internally provided with a mounting cavity; the housing assembly has a first flow port, a second flow port, and a main valve port located between the first flow port and the second flow port; the on-off assembly is movably arranged in the mounting cavity; the on-off assembly is used for controlling the opening and closing of the main valve port so as to realize the on-off of the first flow port and the second flow port; the on-off assembly comprises a piston body and a pilot valve block fixedly arranged on the piston body, and is provided with a through middle channel; one end of the middle channel is communicated with the first flow port, and the other end of the middle channel is provided with a pilot valve port; the pilot valve port is arranged on the pilot valve block, and at least one part of the middle channel is arranged in the piston body; the one-way valve is movably arranged in the middle channel, so that the middle channel can flow in one way; the pilot valve block is fixed on the piston body in a welding mode.

Further, the pilot valve block is welded and fixed on the top end surface of the piston body; or, the top end surface of the piston body is provided with a pilot valve groove, and the pilot valve block is welded and fixed in the pilot valve groove and is in limit fit with the inner wall of the pilot valve groove.

Further, the intermediate passage comprises a piston passage arranged in the piston body and a guide passage arranged in the pilot valve block; the one-way valve is positioned in the piston channel, the one-way valve seals the opening below the guide channel, and the opening above the guide channel is a pilot valve.

Further, at least a portion of the pilot valve block is located within the piston channel, and an outer wall of the pilot valve block is secured to an inner wall of the piston channel by welding.

Further, the inner wall of the piston channel is provided with a step surface, the one-way valve can be in abutting fit with the step surface, and the step surface is used for limiting the movement of the one-way valve in the axial direction.

Further, the wall thickness of each position of the one-way valve is uniform.

Further, the intermediate passage comprises a piston passage arranged in the piston body and a guide passage arranged in the pilot valve block; the inside of the one-way valve is provided with a first flow section and a second flow section which are sequentially communicated from bottom to top, the radial size of the first flow section is larger than that of the second flow section, the side surface of the second flow section is provided with a through hole, and the through hole is used for communicating the second flow section with the piston channel; the wall thickness of the first flow section is equal to the wall thickness of the second flow section.

Further, the inner wall of the piston channel is provided with a step surface, and the step surface is used for limiting the movement of the one-way valve in the axial direction; the one-way valve comprises a first cylindrical part, a second cylindrical part and a round table part which are sequentially connected from bottom to top, the first flow section is positioned in the first cylindrical part, the second flow section is positioned in the second cylindrical part, and the through hole penetrates through the second cylindrical part; the first cylindrical part can be in abutting fit with the step surface; the round platform part is abutted or separated with the opening below the guide channel so as to open and close the guide valve port; both ends of the outer portion of the first cylindrical portion are provided with chamfer structures.

Further, the pilot valve block comprises an insertion section matched with the piston body and a pilot valve section provided with a pilot valve port inside, and the diameter of the insertion section is larger than that of the pilot valve section.

Further, the electromagnetic valve further comprises a piston ring, and the piston ring is sleeved on the on-off assembly and is in sealing fit with the inner wall of the mounting cavity; wherein, the piston ring forms a non-closed annular structure through cutting treatment.

By applying the technical scheme of the utility model, the utility model provides an electromagnetic valve, which comprises the following components: the shell component is internally provided with a mounting cavity; the housing assembly has a first flow port, a second flow port, and a main valve port located between the first flow port and the second flow port; the on-off assembly is movably arranged in the mounting cavity; the on-off assembly is used for controlling the opening and closing of the main valve port so as to realize the on-off of the first flow port and the second flow port; the on-off assembly comprises a piston body and a pilot valve block fixedly arranged on the piston body, and is provided with a through middle channel; one end of the middle channel is communicated with the first flow port, and the other end of the middle channel is provided with a pilot valve port; the pilot valve port is arranged on the pilot valve block, and at least one part of the middle channel is arranged in the piston body; the one-way valve is movably arranged in the middle channel, so that the middle channel can flow in one way; the pilot valve block is fixed on the piston body in a welding mode. According to the utility model, the on-off assembly comprises the piston body and the pilot valve block fixedly arranged on the piston body, the pilot valve port is arranged on the pilot valve block, and at least one part of the middle channel is arranged in the piston body, so that the on-off assembly is easy to process and form; the split-type structure design of the piston body and the pilot valve block can also facilitate the processing and forming of the pilot valve port and the middle channel under the condition of effectively accommodating the one-way valve, so that the processing precision of the pilot valve port and the middle channel is effectively improved, and the actual use requirement is further met; meanwhile, the piston body and the pilot valve block are connected in a welding mode, and the connecting process is simple.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. In the drawings:

FIG. 1 is a schematic diagram showing the structure of a solenoid valve of the prior art;

FIG. 2 is a partial cross-sectional view showing a part of the structure of a solenoid valve according to a first embodiment of the utility model;

FIG. 3 is a partial cross-sectional view showing a part of the structure of a solenoid valve according to a first embodiment of the utility model at another angle;

FIG. 4 is a partial cross-sectional view showing the structure of a solenoid valve according to a second embodiment of the present utility model;

FIG. 5 is a partial cross-sectional view showing the structure of a solenoid valve according to a second embodiment of the utility model at another angle;

FIG. 6 is a schematic view showing the internal structure of a check valve according to an embodiment of the present utility model;

FIG. 7 is a schematic view showing the external structure of a check valve according to an embodiment of the present utility model;

fig. 8 is a schematic view showing an external structure of a lower core according to an embodiment of the present utility model;

fig. 9 is a schematic view showing an internal structure of a lower core according to an embodiment of the present utility model;

fig. 10 shows a schematic diagram of the cooperation of the on-off assembly and the check valve according to an embodiment of the present utility model.

Wherein the above figures include the following reference numerals:

10. a housing assembly; 11. a mounting cavity; 12. a first flow port; 13. a second flow port; 17. a main valve port;

20. an on-off assembly; 21. an intermediate channel; 22. a valve guide port; 23. a piston body; 231. a piston passage; 232. a pilot valve groove; 24. a pilot valve block; 241. an insertion section; 243. a guide channel; 244. a pilot valve section; 25. a regulated pressure channel;

30. a coil assembly;

40. an upper iron core; 41. A guide chamber;

50. a lower iron core; 54. constraining the channel;

60. a lower ejector rod;

80. an elastic member;

90. an upper ejector rod;

110. piston rings;

120. a one-way valve; 121. a first flow-through section; 122. a second circulation segment; 123. a through hole; 124. a first cylindrical portion; 125. a second cylindrical portion; 126. a round table part; 127. chamfering structure.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

As shown in fig. 2 to 10, an embodiment of the present utility model provides a solenoid valve including:

the shell assembly 10, the interior of the shell assembly 10 is provided with a mounting cavity 11; the housing assembly 10 has a first flow port 12, a second flow port 13, and a main valve port 17 located between the first flow port 12 and the second flow port 13;

an on-off assembly 20 movably disposed within the mounting cavity 11; the on-off assembly 20 is used for controlling the opening and closing of the main valve port 17 so as to realize the on-off of the first flow port 12 and the second flow port 13; the on-off assembly 20 comprises a piston body 23 and a pilot valve block 24 fixedly arranged on the piston body 23, and the on-off assembly 20 is provided with a middle channel 21 penetrating through; one end of the middle channel 21 is communicated with the first flow port 12, and the other end of the middle channel 21 is provided with a pilot valve port 22; the pilot valve port 22 is provided on the pilot valve block 24, and at least a portion of the intermediate passage 21 is provided in the piston body 23;

the check valve 120 is movably disposed in the intermediate passage 21 so that the intermediate passage 21 can communicate unidirectionally.

According to the utility model, the on-off assembly 20 comprises a piston body 23 and a pilot valve block 24 fixedly arranged on the piston body 23, the pilot valve opening 22 is arranged on the pilot valve block 24, and at least one part of the middle channel 21 is arranged in the piston body 23, so that the on-off assembly 20 is easy to process and form; the split-type piston body 23 and the pilot valve block 24 are designed to enable the machining and forming of the pilot valve opening 22 and the middle channel 21 to be more convenient and faster under the condition of effectively accommodating the one-way valve 120, so that the machining precision of the pilot valve opening 22 and the middle channel 21 is effectively improved, and the actual use requirement is further met.

By providing the check valve 120, the solenoid valve of the present utility model can be in two-way communication (i.e., the first and second ports 12 and 13 can each be fluid inlets).

Specifically, the pilot valve block 24 is fixed to the piston body 23 by welding. The pilot valve block 24 is fixed on the piston body 23 by welding, so that the pilot valve block 24 can be reliably fixed on one hand, and the pilot valve block 24 is convenient to install on the piston body 23 on the other hand.

As shown in fig. 10, the intermediate passage 21 includes a piston passage 231 provided in the piston body 23 and a guide passage 243 provided in the pilot valve block 24; the pilot valve block 24 is welded and fixed on the top end surface of the piston body 23; alternatively, the top end surface of the piston body 23 is provided with a pilot valve groove 232, and the pilot valve block 24 is welded and fixed in the pilot valve groove 232 and is in limit fit with the inner wall of the pilot valve groove 232; alternatively, at least a portion of the pilot valve block 24 is located within the piston channel 231, with the outer wall of the pilot valve block 24 being secured to the inner wall of the piston channel 231 by welding. One of the three modes is flexibly selected according to the actual use requirement, so that the pilot valve block 24 is reliably fixed on the piston body 23.

As shown in fig. 10, the intermediate passage 21 includes a piston passage 231 provided in the piston body 23 and a guide passage 243 provided in the pilot valve block 24; the check valve 120 is positioned in the piston channel 231, the check valve 120 seals the opening below the guide channel 243, and the opening above the guide channel 243 is the pilot valve 22. By the arrangement, the structure of the middle channel 21 is simplified, the one-way valve 120 works reliably, and the two-way circulation of the electromagnetic valve is realized.

As shown in fig. 10, the inner wall of the piston channel 231 is provided with a stepped surface, with which the check valve 120 can be in abutting engagement, for restricting movement of the check valve 120 in the axial direction. By providing the step surface, the check valve 120 is effectively limited in the axial direction; by setting specific dimension parameters of the step surface, the axial stroke of the check valve 120 can be effectively controlled to adapt to different use requirements.

Optionally, the wall thickness is uniform at each location of the check valve 120. This arrangement ensures that the check valve 120 is easy to machine.

As shown in fig. 6, 7 and 10, the intermediate passage 21 includes a piston passage 231 provided in the piston body 23 and a guide passage 243 provided in the pilot valve block 24; the inside of the check valve 120 is provided with a first flow section 121 and a second flow section 122 which are sequentially communicated from bottom to top, the radial dimension of the first flow section 121 is larger than that of the second flow section 122, the side surface of the second flow section 122 is provided with a through hole 123, and the through hole 123 communicates the second flow section 122 with the piston channel 231; the wall thickness of the first flow-through section 121 is equal to the wall thickness of the second flow-through section 122. By the arrangement, the check valve 120 is easy to integrally machine and form, and the check valve 120 is convenient to install and reliable in operation.

As shown in fig. 6, 7 and 10, the inner wall of the piston passage 231 is provided with a stepped surface for restricting the movement of the check valve 120 in the axial direction; the one-way valve 120 comprises a first cylindrical part 124, a second cylindrical part 125 and a round table part 126 which are sequentially connected from bottom to top, the first flow section 121 is positioned in the first cylindrical part 124, the second flow section 122 is positioned in the second cylindrical part 125, and the through hole 123 penetrates through the second cylindrical part 125; the first cylindrical portion 124 may be in abutting engagement with the step surface; the truncated cone 126 abuts against or separates from the opening below the guide passage 243 to open and close the pilot valve port 22; both ends of the outside of the first cylindrical portion 124 are provided with chamfer structures 127. By providing the chamfer structure 127, the check valve 120 is easy to install; by arranging the round table portion 126, the one-way valve 120 can effectively control the on-off of the opening below the guide channel 243, and further realize the bidirectional circulation of the electromagnetic valve.

As shown in fig. 2, 3 and 10, the pilot valve block 24 includes an insertion section 241 engaged with the piston body 23 and a pilot valve section 244 having the pilot valve port 22 provided therein, the insertion section 241 having a diameter larger than that of the pilot valve section 244. This arrangement ensures a reliable fixing of the pilot valve block 24 on the piston body 23.

As shown in fig. 2, 3, 4 and 5, the electromagnetic valve further comprises a piston ring 110, wherein the piston ring 110 is sleeved on the on-off assembly 20 and is in sealing fit with the inner wall of the installation cavity 11; wherein the piston ring 110 is formed into a non-closed ring structure by a cutting process. By arranging the piston ring 110, the tightness between the on-off assembly 20 and the mounting cavity 11 is ensured; the piston ring 110 is cut off to form a non-closed annular structure, so that the deformation of the piston ring 110 is larger, the applicability of the piston ring 110 is improved, and the problem of inconvenient installation of the piston ring 110 caused by the large overall size is avoided.

As shown in fig. 2, 3, 4 and 5, the solenoid valve further includes: a coil assembly 30 disposed on the housing assembly 10; an upper core 40 movably disposed in the installation cavity 11; a lower core 50 movably and elastically disposed in the installation cavity 11 and positioned below the upper core 40; the intermediate passage 21 includes a piston passage 231 provided in the piston body 23 and a guide passage 243 provided in the pilot valve block 24; the elastic piece 80 and the upper ejector rod 90, the lower iron core 50 is elastically arranged in the installation cavity 11 through the elastic piece 80 and the upper ejector rod 90; the upper iron core 40 is internally provided with a guide cavity 41 extending along the axial direction, and at least one part of the upper ejector rod 90 is positioned in the guide cavity 41; one end of the elastic member 80 is abutted against the housing assembly 10, and the other end is abutted against one end of the upper ejector rod 90; the other end of the upper ejector rod 90 is abutted with the lower iron core 50; the inside of the on-off assembly 20 is also provided with a pressure stabilizing channel 25, two ends of the pressure stabilizing channel 25 are respectively communicated with the upper part and the lower part of the on-off assembly 20, and the lower part of the on-off assembly 20 is communicated with the second flow port 13; a lower ejector rod 60 movably arranged in the installation cavity 11; one end of the lower ejector rod 60 is in abutting fit with the upper iron core 40, and the other end of the lower ejector rod 60 is in abutting fit with the on-off assembly 20; as shown in fig. 8 and 9, the lower core 50 has a constraining passage 54 thereon, and an inner wall of the constraining passage 54 cooperates with the lower ejector pin 60 to constrain the lower ejector pin 60 to reciprocate in a straight line in the up-down direction. By the arrangement, the working reliability of the electromagnetic valve is guaranteed, and the structure of the electromagnetic valve tends to be simplified.

It should be noted that: the upper iron core 40 and the lower iron core 50 in the utility model have shorter action strokes, so that the on-off of high frequency can be realized, and the service life of the electromagnetic valve is effectively prolonged.

The specific working process of the electromagnetic valve provided by the utility model in bidirectional circulation is now described in detail:

when the high-pressure medium fluid flows from the first flow port 12 to the second flow port 13, the on-off assembly 20 is blocked at the main valve port 17 in a state that the coil assembly 30 is powered off, and the electromagnetic valve is in a closed state; in the state that the coil assembly 30 is electrified, the upper iron core 40 adsorbs the lower iron core 50 to move towards the upper iron core 40, the pilot valve opening 22 is opened, the high-pressure medium fluid pushes the one-way valve 120 upwards to move, the one-way valve 120 seals the opening below the guide channel 243 so as to seal the valve guide opening 22, the high-pressure medium fluid cannot enter the upper part of the on-off assembly 20 from the first flow opening 12 through the pilot valve opening 22, the high-pressure state above the on-off assembly 20 is eliminated, the on-off assembly 20 moves upwards under the action of the high-pressure medium fluid, the main valve opening 17 is opened, the first flow opening 12 and the second flow opening 13 are kept in a communicated state, and the high-pressure medium fluid circulates;

when the high-pressure medium fluid flows from the second flow port 13 to the first flow port 12, the solenoid valve is in a closed state in a state where the coil assembly 30 is powered off, and the high-pressure medium fluid does not circulate; in the energized state of the coil assembly 30, the upper iron core 40 adsorbs the lower iron core 50 to move towards the upper iron core 40, the pilot valve opening 22 is opened, the one-way valve 120 is arranged at intervals with the opening below the guide channel 243 under the action of pressure difference, high-pressure medium fluid above the on-off assembly 20 flows to the first flow opening 12 through the pilot valve opening 22, the middle channel 21 and the inside of the one-way valve 120, a low-pressure area is formed above the on-off assembly 20, the on-off assembly 20 moves upwards under the action of high pressure below the on-off assembly 20, the main valve opening 17 is opened, the second flow opening 13 and the first flow opening 12 are kept in a communicated state, and the high-pressure medium fluid flows.

In summary, the present utility model provides a solenoid valve, in which the on-off assembly 20 includes a piston body 23 and a pilot valve block 24 fixedly disposed on the piston body 23, the pilot valve 22 is disposed on the pilot valve block 24, and at least a portion of the intermediate channel 21 is disposed in the piston body 23, so that the on-off assembly 20 is easy to process and form; the split-type piston body 23 and the pilot valve block 24 are designed to enable the machining and forming of the pilot valve opening 22 and the middle channel 21 to be more convenient and faster under the condition of effectively accommodating the one-way valve 120, so that the machining precision of the pilot valve opening 22 and the middle channel 21 is effectively improved, and the actual use requirement is further met.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present utility model unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present utility model, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present utility model; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present utility model.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A solenoid valve, comprising:

the shell assembly (10), the said shell assembly (10) is the installation cavity (11); -the housing assembly (10) has a first flow port (12), a second flow port (13) and a main valve port (17) between the first flow port (12) and the second flow port (13);

an on-off assembly (20) movably arranged in the mounting cavity (11); the on-off assembly (20) is used for controlling the opening and closing of the main valve opening (17) so as to realize the on-off of the first flow opening (12) and the second flow opening (13); the on-off assembly (20) comprises a piston body (23) and a pilot valve block (24) fixedly arranged on the piston body (23), and the on-off assembly (20) is provided with a through middle channel (21); one end of the middle channel (21) is communicated with the first flow port (12), and the other end of the middle channel (21) is provided with a pilot valve port (22); the pilot valve opening (22) is arranged on the pilot valve block (24), and at least one part of the middle channel (21) is arranged in the piston body (23);

a one-way valve (120) movably disposed within the intermediate passage (21) such that the intermediate passage (21) is capable of one-way flow;

the pilot valve block (24) is fixed on the piston body (23) in a welding mode.

2. The solenoid valve according to claim 1, characterized in that said pilot valve block (24) is welded fixed on the top end face of said piston body (23); or the top end surface of the piston body (23) is provided with a pilot valve groove (232),

the pilot valve block (24) is fixedly welded in the pilot valve groove (232) and is in limit fit with the inner wall of the pilot valve groove (232).

3. The solenoid valve according to claim 1, characterized in that the intermediate channel (21) comprises a piston channel (231) provided in the piston body (23) and a guide channel (243) provided in the pilot valve block (24); the check valve (120) is positioned in the piston channel (231), the check valve (120) seals an opening below the guide channel (243), and an opening above the guide channel (243) is the guide valve port (22).

4. A solenoid valve according to claim 3, characterised in that at least a part of said pilot valve block (24) is located in said piston channel (231), the outer wall of said pilot valve block (24) being secured to the inner wall of said piston channel (231) by welding.

5. A solenoid valve according to claim 3, characterised in that the inner wall of the piston channel (231) is provided with a stepped surface with which the non-return valve (120) can be in abutment fit, said stepped surface being adapted to limit the movement of the non-return valve (120) in the axial direction.

6. The solenoid valve of claim 1 wherein said one-way valve (120) has a uniform wall thickness at each location.

7. The solenoid valve according to claim 1, characterized in that the intermediate channel (21) comprises a piston channel (231) provided in the piston body (23) and a guide channel (243) provided in the pilot valve block (24); the inside of the one-way valve (120) is provided with a first flowing section (121) and a second flowing section (122) which are sequentially communicated from bottom to top, the radial size of the first flowing section (121) is larger than that of the second flowing section (122), the side surface of the second flowing section (122) is provided with a through hole (123), and the through hole (123) is used for communicating the second flowing section (122) with the piston channel (231); the wall thickness of the first flow section (121) is equal to the wall thickness of the second flow section (122).

8. The solenoid valve according to claim 7, characterized in that the inner wall of the piston channel (231) is provided with a stepped surface for limiting the movement of the one-way valve (120) in the axial direction; the one-way valve (120) comprises a first cylindrical part (124), a second cylindrical part (125) and a round table part (126) which are sequentially connected from bottom to top, the first flow section (121) is positioned in the first cylindrical part (124), the second flow section (122) is positioned in the second cylindrical part (125), and the through hole (123) penetrates through the second cylindrical part (125); the first cylindrical part (124) can be in abutting fit with the step surface; the round platform part (126) is abutted with or separated from an opening below the guide channel (243) so as to open and close the pilot valve opening (22); both ends of the outside of the first cylindrical part (124) are provided with chamfering structures (127).

9. The solenoid valve according to claim 1, characterized in that said pilot valve block (24) comprises an insertion section (241) cooperating with said piston body (23) and a pilot valve section (244) inside which said pilot valve opening (22) is provided, the diameter of said insertion section (241) being greater than the diameter of said pilot valve section (244).

10. The electromagnetic valve according to claim 1, characterized in that it further comprises a piston ring (110), said piston ring (110) being fitted over said on-off assembly (20) and being in sealing engagement with the inner wall of said mounting cavity (11); wherein the piston ring (110) is formed into a non-closed ring structure by a cutting process.